JP2016038403A - Liquid developer, developer cartridge, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid developer that has excellent positive chargeability.SOLUTION: A liquid developer contains a carrier liquid, and toner particles including a styrene-acrylic resin subjected to surface treatment with polymeric amines.SELECTED DRAWING: None

Description

  The present invention relates to a liquid developer, a developer cartridge, a process cartridge, and an image forming apparatus.

  A method of visualizing image information through an electrostatic charge image such as electrophotography is currently used in various fields. In electrophotography, a latent image (electrostatic latent image) is formed on an image carrier by a charging and exposure process (latent image forming process), and an electrostatic charge image developing toner (hereinafter simply referred to as “toner”). The electrostatic latent image is developed (development process) with a developer for developing electrostatic images (hereinafter sometimes referred to simply as “developer”), and visualized through a transfer process and a fixing process. The Developers used in the dry development method include a two-component developer composed of a toner and a carrier, and a one-component developer using a magnetic toner or a non-magnetic toner alone.

  On the other hand, the liquid developer used in the wet development system is one in which toner particles are dispersed in an insulating carrier liquid, and a type in which toner particles containing a thermoplastic resin are dispersed in a volatile carrier liquid. A type in which toner particles containing a thermoplastic resin are dispersed in a hardly volatile carrier liquid is known.

For example, Patent Document 1 discloses a positively chargeable liquid developer in which toner particles are dispersed in an insulating liquid, and the toner particles include mother particles having an anionic group on the surface, a cationic group and a hydrophobic group. A liquid developer is described which is coated with a polymer layer having a repeating structural unit derived from a cationic polymerizable surfactant having a polymerizable group and a polymerizable group.

  Patent Document 2 describes a liquid developer containing an insulating liquid and toner particles obtained by surface-modifying toner particles containing a rosin resin with polyalkyleneimine.

  Patent Document 3 describes a black toner in which toner base particles containing carbon black as a colorant and a binder resin are surface-modified with polyalkyleneimine.

JP 2007-114226 A JP 2010-025971 A JP 2010-026236 A

  An object of the present invention is to provide a liquid developer excellent in positive chargeability, a developer cartridge using the liquid developer, a process cartridge, and an image forming apparatus.

  The invention according to claim 1 is a liquid developer containing a carrier liquid and toner particles containing a styrene acrylic resin that has been surface-treated with a polymeric amine.

  The invention according to claim 2 is the liquid developer according to claim 1, wherein the styrene acrylic resin has an acidic group in a molecule.

  The invention according to claim 3 is the liquid developer according to claim 1 or 2, wherein the polymeric amine is a polyalkyleneimine.

The invention according to claim 4 is the liquid developer according to claim 1 or 2, wherein the polymeric amine is a polyallylamine represented by the following general formula (I).

(I)
(In formula (I), R ¹ and R ² each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 20 carbon atoms, and a and b each independently represent 100 to 1,000. The following integers are shown.)

The invention according to claim 5 is the liquid developer according to any one of claims 1 to 4, wherein the carrier liquid contains a carboxyl group-containing silicone compound represented by the following general formula (II). .

(II)
(In the formula (II), X, Y and Z each independently represent a hydrogen atom or a carboxyl group, and at least one of X, Y and Z represents a carboxyl group. N is an integer of 1 to 10. R ³ , R ⁴ and R ⁵ are each independently a single bond or a divalent aliphatic carbon atom having 1 to 20 carbon atoms. Indicates a hydrogen group.)

The invention according to claim 6 includes an olefin / maleic acid derivative copolymer having a polysiloxane structure in the main chain or side chain represented by the following formula (III) in the carrier liquid. The liquid developer according to any one of the above.

(III)
(In Formula (III), A ¹ represents NR ¹ R ² or OR ¹ , and R ¹ and R ² are each independently a hydrogen atom, or an aliphatic group having 1 to 20 carbon atoms that may be substituted, or Represents an aromatic hydrocarbon group, A ² represents R ³ or OR ³ , R ³ represents an optionally substituted aliphatic or aromatic hydrocarbon group having 1 to 20 carbon atoms, and X represents a main chain Or a divalent organic group having a polysiloxane structure in the side chain, j and k each independently represent an integer of 1 to 1,000, and l represents an integer of 1 to 100.)

  The invention according to claim 7 is a developer cartridge in which the liquid developer according to any one of claims 1 to 6 is accommodated.

  The invention according to claim 8 is a process cartridge in which the liquid developer according to any one of claims 1 to 6 is accommodated.

  According to a ninth aspect of the present invention, there is provided an image carrier, a latent image forming unit that forms a latent image on the surface of the image carrier, and the latent image formed on the surface of the image carrier. A developing means for forming a toner image by developing with the liquid developer according to any one of claims 1 to 6 held on the surface of the toner, and the toner image formed on the surface of the image carrier. An image forming apparatus comprising: transfer means for transferring onto a recording medium; and fixing means for fixing the toner image transferred to the recording medium to the recording medium to form a fixed image.

  According to the first aspect of the present invention, there is provided a liquid developer that is excellent in positive chargeability as compared with a case where toner particles containing a styrene acrylic resin are not surface-treated.

  According to the second aspect of the present invention, there is provided a liquid developer that is excellent in positive chargeability as compared with the case where the styrene acrylic resin does not have an acidic group in the molecule.

  According to the third aspect of the present invention, there is provided a liquid developer excellent in positive chargeability as compared with the case where the polymeric amine is not a polyalkyleneimine.

  According to the fourth aspect of the present invention, there is provided a liquid developer excellent in positive chargeability as compared with the case where the polymeric amine is not the polyallylamine represented by the general formula (I).

  According to the fifth aspect of the present invention, there is provided a liquid developer which is excellent in positive chargeability as compared with the case where the carrier liquid does not contain the carboxyl group-containing silicone compound represented by the above formula (II).

  According to the invention which concerns on Claim 6, compared with the case where the carrier liquid does not contain the olefin / maleic acid derivative copolymer having a polysiloxane structure in the main chain or side chain represented by the above formula (III). A liquid developer having excellent positive chargeability is provided.

  According to the seventh aspect of the present invention, there is provided a developer cartridge that contains a liquid developer that is excellent in positive chargeability as compared with the case where the toner particles containing styrene acrylic resin of the liquid developer are not surface-treated. Provided.

  According to the eighth aspect of the present invention, there is provided a process cartridge in which a liquid developer that is superior in positive chargeability as compared with a case where toner particles containing styrene acrylic resin of the liquid developer are not surface-treated is provided. Is done.

  According to the ninth aspect of the present invention, there is provided an image forming apparatus using a liquid developer that is superior in positive chargeability as compared with a case where toner particles containing styrene acrylic resin of the liquid developer are not surface-treated. .

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

<Liquid developer>
The liquid developer according to the exemplary embodiment includes a carrier liquid and toner particles including a styrene acrylic resin that has been surface-treated with polymer amines.

  A liquid developer in which toner particles containing a styrene acrylic resin as a binder resin are dispersed in a carrier liquid has been studied. However, it is difficult to positively charge the liquid developer in a carrier liquid, particularly in silicone oil. there were. In this embodiment, in a liquid developer in which toner particles containing styrene acrylic resin as a binder resin are dispersed in a carrier liquid, toner particles that are surface-treated with polymer amines are used as toner particles. A liquid developer having positive charging characteristics is realized.

  The reason why the positive chargeability is excellent by using the liquid developer according to this embodiment is because, for example, in this liquid developer, high-cationic polymer amines are firmly attached to the surface of the toner particles. it is conceivable that.

  Hereinafter, the components of the liquid developer according to this embodiment will be described in detail.

[Toner particles]
The toner particles contained in the liquid developer according to the exemplary embodiment include a binder resin, and may include other components such as a colorant and a release agent as necessary. The toner particles are surface-treated with high molecular amines. By using toner particles surface-treated with polymer amines, positive chargeability is imparted to the liquid developer.

  Examples of the polymer amines include polyalkyleneimines, polyallylamines, polydiallylamines and the like. Of these, polyalkylenimines and polyallylamines are preferred from the viewpoints of high cationicity and easy positive charging.

  Examples of the polyalkyleneimines include polyethyleneimine.

Examples of polyallylamines include polyallylamines represented by the following general formula (I).

(I)
(In formula (I), R ¹ and R ² each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 20 carbon atoms, and a and b each independently represent 100 to 1,000. The following integers are shown.)

R ¹ and R ² are a hydrogen atom or an aliphatic hydrocarbon group having 1 to 20 carbon atoms, preferably an aliphatic hydrocarbon group having 1 to 20 carbon atoms. Examples of the aliphatic hydrocarbon group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a linear or branched propyl group, a butyl group, a pentyl group, a hexyl group, and an octyl group, and a methyl group is preferable.

  a and b are each independently an integer of 1 to 10,000, preferably an integer of 5 to 1,000.

  The amount of the polymeric amine with respect to the toner particles is preferably in the range of 0.01 parts by weight to 100 parts by weight, for example, in the range of 0.1 parts by weight to 10 parts by weight with respect to 100 parts by weight of the toner particles. A range is more preferable. If the amount of the polymeric amine with respect to the toner particles is less than 0.01 parts by mass with respect to 100 parts by mass of the toner particles, the chargeability may be inferior. If the amount exceeds 100 parts by mass, the conductivity of the developer is high. In some cases, the chargeability may decrease.

  The weight average molecular weight of the polymeric amines is preferably in the range of 100 to 1,000,000, more preferably in the range of 1,000 to 100,000. When the weight average molecular weight of the polymeric amine is less than 100, the adsorptivity to the toner surface is low, and the target charging performance may not be obtained. Adhesion may occur.

(Binder resin)
The binder resin for toner particles contains styrene acrylic resin as a main component. The main component means 50 parts by mass or more with respect to 100 parts by mass of the binder resin in the toner particles.

  A styrene acrylic resin is a copolymer of a styrene monomer and an acrylic monomer, or a copolymer of a styrene monomer, an acrylic monomer, and one or more other vinyl monomers. It is a coalescence.

  Examples of the styrene monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, and pn-butylstyrene. , P-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichloro Styrene etc. are mentioned, only 1 type may be used and 2 or more types of monomers may be used together.

  Examples of the acrylic monomer include acrylic acid, methacrylic acid, acrylic acid ester, and methacrylic acid ester. One type may be used alone, or two or more types may be used in combination.

  Specific examples of the acrylate ester and methacrylate ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, and (meth) acrylic acid. In addition to alkyl esters of (meth) acrylic acid such as isobutyl, n-octyl (meth) acrylate, dodecyl (meth) acrylate, 2-ethylhexyl acrylate, stearyl (meth) acrylate, 2-chloroethyl acrylate, ( (Meth) acrylic acid phenyl, α-methyl chloroacrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, glycidyl (meth) acrylate, Dimethylaminoethyl methacrylate, diethylamethacrylate Aminoethyl, bisglycidyl methacrylate, polyethylene glycol dimethacrylate, methacryloxyethyl phosphate, and the like, may be used alone or in combination of two or more thereof. The above “(meth) acryl” means either or both of acrylic and methacrylic.

  Examples of the vinyl monomer include olefin monomers such as ethylene, propylene, butylene, butadiene, and isoprene; vinyl ester monomers such as vinyl formate, vinyl acetate, vinyl propionate, and vinyl benzoate; Unsaturated dicarboxylic acid such as acid, maleic acid, citraconic acid, itaconic acid and the monoester derivative or diester derivative thereof; mono (meth) acryloyloxyethyl ester of succinic acid, (meth) acrylonitrile, acrylamide, etc. Or two or more of them may be used in combination.

  The weight average molecular weight Mw of the styrene acrylic resin is preferably in the range of 100,000 to 1,000,000. If the weight average molecular weight Mw of the styrene acrylic resin is less than 100,000, the toner particle strength or the strength of the image after fixing may be insufficient, and if it exceeds 1,000,000, the fixability is poor. There is a case.

  The weight average molecular weight (Mw) of the binder resin or the like is measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC is performed with a THF solvent using a Tosoh GPC / HLC-8120 as a measuring device and a Tosoh column / TSKgel Super HM-M (15 cm). The weight average molecular weight is calculated from the measurement result using a molecular weight calibration curve prepared with a monodisperse polystyrene standard sample.

  The styrene acrylic resin preferably has an acidic group in the molecule. It is considered that when the styrene acrylic resin has an acidic group in the molecule, polymer amines easily adhere to the surface of the toner, and is more excellent in positive chargeability. Examples of the acidic group include a carboxyl group and a sulfonic acid group.

  The acid value of the styrene acrylic resin is preferably in the range of 1 mgKOH / g to 50 mgKOH / g, and more preferably in the range of 5 mgKOH / g to 20 mgKOH / g. If the acid value of the styrene acrylic resin is less than 1 mgKOH / g, positive charging may be insufficient, and if it exceeds 50 mgKOH / g, the chargeability may be lowered.

  The toner according to the exemplary embodiment may include a resin other than the styrene acrylic resin. Although it does not restrict | limit especially as resin other than a styrene acrylic resin, For example, an epoxy resin, a polyester resin, a polyurethane resin, a polyamide resin, a cellulose resin, a polyether resin etc. are mentioned. These resins may be used alone or in combination of two or more.

  The content of the binder resin is, for example, in the range of 80% by mass to 95% by mass with respect to the entire toner particles.

  The toner particles according to the exemplary embodiment may contain other additives such as a colorant, a release agent, a charge control agent, silica powder, and a metal oxide as necessary. These additives may be added internally by, for example, kneading into a binder resin, or may be added externally by, for example, mixing the particles after obtaining toner particles.

  There is no restriction | limiting in particular as a coloring agent, A well-known pigment is used, A well-known dye may be included as needed. Specifically, the following pigments such as yellow, magenta, cyan, and black (black) are used.

  As yellow pigments, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complex compounds, methine compounds, allylamide compounds and the like are used.

  As magenta pigments, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds, and the like are used.

  Examples of cyan pigments include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like.

  As the black pigment, carbon black, aniline black, acetylene black, iron black and the like are used.

  The content of the colorant is, for example, in the range of 5% by mass to 20% by mass with respect to the entire toner particles.

  The release agent is not particularly limited, and examples thereof include plant waxes such as carnauba wax, wood wax and rice bran wax; animal waxes such as bees wax, insect wax, whale wax and wool wax; minerals such as montan wax and ozokerite. Synthetic waxes, synthetic fatty acid solid ester waxes such as Fischer-Tropsch wax (FT wax) having ester side chains, special fatty acid esters, polyhydric alcohol esters; paraffin wax, polyethylene wax, polypropylene wax, polytetrafluoroethylene wax, polyamide wax And synthetic waxes such as silicone compounds. A mold release agent may be used individually by 1 type, and may use 2 or more types together.

  The content of the release agent is, for example, in the range of 0.1% by mass to 10% by mass with respect to the entire toner particles.

  There is no restriction | limiting in particular as a charge control agent, A conventionally well-known charge control agent is used. For example, positively chargeable charge control agents such as nigrosine dyes, fatty acid-modified nigrosine dyes, carboxyl group-containing fatty acid-modified nigrosine dyes, quaternary ammonium salts, amine compounds, amide compounds, imide compounds, organometallic compounds; oxycarboxylic acids And negatively chargeable charge control agents such as metal complexes of azo compounds, metal complex dyes and salicylic acid derivatives. A charge control agent may be used individually by 1 type, and may use 2 or more types together.

  The metal oxide is not particularly limited, and examples thereof include titanium oxide, aluminum oxide, magnesium oxide, zinc oxide, strontium titanate, barium titanate, magnesium titanate, and calcium titanate. A metal oxide may be used individually by 1 type, and may use 2 or more types together.

(Method for producing toner particles)
The method for producing the toner particles used in the present embodiment is not particularly limited, and is obtained by, for example, pulverizing toner produced by a production method such as pulverized toner, emulsion-dried toner in liquid, or polymerized toner in a carrier liquid. It is done.

  For example, binder resin, and if necessary, colorant, other additives, etc. are put into a mixing device such as a Henschel mixer and mixed, and this mixture is melted with a twin screw extruder, Banbury mixer, roll mill, kneader, etc. After kneading, cooling with a drum flaker, etc., coarsely pulverizing with a pulverizer such as a hammer mill, and further pulverizing with a pulverizer such as a jet mill, followed by classification using an air classifier, etc. can get.

  Also, the binder resin, if necessary, the colorant and other additives were dissolved in a solvent such as ethyl acetate, and emulsified and suspended in water to which a dispersion stabilizer such as calcium carbonate was added, and the solvent was removed. Thereafter, particles obtained by removing the dispersion stabilizer are filtered and dried to obtain an in-liquid emulsified dry toner.

  In addition, a polymerizable monomer, a colorant, and a polymerization initiator (for example, benzoyl peroxide, lauroyl peroxide, isopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichloroylbenzoyl peroxide) that form a binder resin , Methyl ethyl ketone peroxide, etc.) and other additives are added to the aqueous phase under stirring and granulated. After the polymerization reaction, the particles are filtered and dried to obtain a polymerized toner.

  The mixing ratio of each material (binder resin, colorant, other additives, etc.) for obtaining the toner may be set in consideration of required characteristics, low temperature fixability, color, and the like. The obtained toner is pulverized in carrier oil using a known pulverizer such as a ball mill, a bead mill, a high-pressure wet atomizer, etc., thereby obtaining toner particles for the liquid developer of this embodiment.

  In the present embodiment, in the case of surface treatment with polymer amines, from the viewpoint of ease of surface treatment with polymer amines, the toner particles containing styrene acrylic resin are resin particles and colorant containing styrene acrylic resin. Toner particles obtained by aggregating a dispersion containing the particles in an aqueous medium are preferred. Since the polymer amines are water-soluble polymers, in the wet production method in which the granules are granulated in the liquid, the polymer amines may be adsorbed on the toner particle surfaces as they are after washing with water before the drying step.

(Characteristics of toner particles)
The volume average particle diameter D50v of the toner particles is preferably 0.5 μm or more and 5.0 μm or less. By being in the said range, adhesive force is high and developability is improved. In addition, the resolution of the image can be improved. The volume average particle diameter D50v of the toner particles is more preferably in the range of 0.8 μm or more and 4.0 μm or less, and further preferably in the range of 1.0 μm or more and 3.0 μm or less.

For the volume average particle size D50v, number average particle size distribution index (GSDp), volume average particle size distribution index (GSDv), etc. of the toner particles, a laser diffraction / scattering type particle size distribution measuring device such as LA920 (manufactured by Horiba Ltd.) is used. Measured. Draw a cumulative distribution from the smaller diameter side for each particle size range (channel) divided based on the particle size distribution, and particles with a cumulative particle size of 16%, volume D16v, number D16p, and cumulative 50% The diameter is defined as volume D50v, number D50p, and the particle diameter at 84% cumulative is defined as volume D84v, number D84p. Using these, the volume average particle size distribution index (GSDv) is calculated as (D84v / D16v) ^1/2 and the number average particle size distribution index (GSDp) is calculated as (D84p / D16p) ^1/2 .

[Carrier liquid]
The carrier liquid is an insulating liquid for dispersing toner particles. Silicone oils (silicone solvents such as dimethyl silicone, diphenyl silicone, and hydrogen-modified silicone compounds having a degree of polymerization of greater than 20 and cyclic siloxane compounds) ) And the like. Of these, dimethyl silicone is preferable from the viewpoint of viscosity, dispersibility, and the like. “Containing silicone oil as the main component” means containing 50 mass% or more of silicone oil in the carrier liquid.

  The carrier liquid contained in the liquid developer according to the exemplary embodiment may be only one type or two or more types. In the case where the carrier liquid is used as a mixed system of two or more kinds, for example, a mixed system of a silicone solvent and vegetable oil can be used.

Examples of the volume resistivity of the carrier liquid include a range of 1.0 × 10 ¹⁰ Ω · cm to 1.0 × 10 ¹⁴ Ω · cm, and 1.0 × 10 ¹² Ω · cm to 1.0 × It may be in the range of 10 ¹⁴ Ω · cm or less.

  The viscosity of the carrier liquid is preferably in the range of 1 mPas to 100 mPas in terms of steady shear viscosity at 25 ° C. More preferably, it is the range of 1 mPas or more and 80 mPas or less, More preferably, it is the range of 1 mPas or more and 60 mPas or less. When the steady shear viscosity is less than 1 mPas, the molecular weight of silicone oil or the like may be lowered. On the other hand, if the steady shear viscosity is higher than 100 mPas, the viscosity of the developer using this carrier oil increases, so that required characteristics may not be obtained.

  The carrier liquid is made of various auxiliary materials such as dispersants, emulsifiers, surfactants, stabilizers, wetting agents, thickeners, foaming agents, antifoaming agents, coagulants, gelling agents, anti-settling agents, charging agents. It may contain a control agent, an antistatic agent, an anti-aging agent, a softening agent, a plasticizer, a filler, a flavoring agent, an anti-tacking agent, a release agent and the like.

  The liquid developer according to the exemplary embodiment preferably contains a carboxyl group-containing silicone compound. In a liquid developer in which toner particles containing styrene acrylic resin as a binder resin are dispersed in a carrier liquid, toner particles surface-treated with polymer amines are used as toner particles, and a carboxyl group-containing silicone compound is contained. By doing so, a liquid developer having more excellent positive charging characteristics is realized.

Examples of the carboxyl group-containing silicone compound include compounds represented by the following formula (II). The compound represented by the following general formula (II) is highly cationic and easily positively charged.

(II)
(In the formula (II), X, Y and Z each independently represent a hydrogen atom or a carboxyl group, and at least one of X, Y and Z represents a carboxyl group. N is an integer of 1 to 10. R ³ , R ⁴ and R ⁵ are each independently a single bond or a divalent aliphatic carbon atom having 1 to 20 carbon atoms. Indicates a hydrogen group.)

  In formula (II), even if one of X, Y and Z is a carboxyl group, or two of X, Y and Z are carboxyl groups, all of X, Y and Z are carboxyl groups. May be.

In the formula (II), R ³ , R ⁴ and R ⁵ are each independently a single bond or a divalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, and a single bond or 3 to 12 carbon atoms. These divalent aliphatic hydrocarbon groups are preferred. Examples of the divalent aliphatic hydrocarbon group having 1 to 20 carbon atoms include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a hexamethylene group, an octamethylene group, a decamethylene group, an undecamethylene group, and a dodecamethylene group. Hexadecamethylene group, octadecamethylene group and the like, and trimethylene group, tetramethylene group, hexamethylene group, octamethylene group, decamethylene group, undecamethylene group, dodecamethylene group and the like are preferable.

  In the formula (II), m is an integer of 1 to 1,000, and preferably an integer of 5 to 100. In the formula (II), n is an integer of 1 to 10, and preferably an integer of 1 to 5.

  The amount of the carboxyl group-containing silicone compound in the liquid developer is, for example, preferably in the range of 0.001 to 10 parts by mass with respect to 100 parts by mass of the liquid developer, and 0.01 to 1 part by mass. More preferably, it is in the range of less than or equal to parts by mass. When the amount of the carboxyl group-containing silicone compound relative to the liquid developer is less than 0.001 part by mass with respect to 100 parts by mass of the liquid developer, the chargeability may be inferior. When the amount exceeds 10 parts by mass, the conductivity is high. In some cases, the chargeability may be lowered.

  The weight average molecular weight of the carboxyl group-containing silicone compound is preferably in the range of 100 to 100,000, and more preferably in the range of 1,000 to 10,000. If the weight average molecular weight of the carboxyl group-containing silicone compound is less than 100, the compatibility with the liquid developer may not be sufficient, and if it exceeds 100,000, the fixability of the developer may be inhibited.

  The liquid developer according to the exemplary embodiment preferably contains an olefin / maleic acid derivative copolymer having a polysiloxane structure in the main chain or side chain. In a liquid developer in which toner particles containing styrene acrylic resin as a binder resin are dispersed in a carrier liquid, toner particles surface-treated with polymer amines are used as toner particles, and the main chain or side chain is made of poly. By including an olefin / maleic acid derivative copolymer having a siloxane structure, a liquid developer having better positive charging characteristics is realized.

  For example, in this liquid developer, polymer amines having high cationicity are firmly attached to the surface of the toner particles, whereas the main chain or side chain has a polysiloxane structure. It is considered that the olefin / maleic acid derivative copolymer possessed forms a counter anion.

Examples of the olefin / maleic acid derivative copolymer having a polysiloxane structure in the main chain or side chain include compounds represented by the following general formula (III).

(III)
(In Formula (III), A ¹ represents NR ¹ R ² or OR ¹ , and R ¹ and R ² are each independently a hydrogen atom, or an aliphatic group having 1 to 20 carbon atoms that may be substituted, or Represents an aromatic hydrocarbon group, A ² represents R ³ or OR ³ , R ³ represents an optionally substituted aliphatic or aromatic hydrocarbon group having 1 to 20 carbon atoms, and X represents a main chain Or a divalent organic group having a polysiloxane structure in the side chain, j and k each independently represent an integer of 1 to 1,000, and l represents an integer of 1 to 100.)

Examples of the compound represented by the general formula (III) include a compound represented by the following general formula (IV), a compound represented by the following general formula (V), a compound represented by the following general formula (VI), and the like. Can be mentioned.

(IV)
(In formula (IV), A ¹ represents NR ¹ R ² or OR ¹ , and R ¹ and R ² are each independently a hydrogen atom, or an aliphatic group having 1 to 20 carbon atoms which may be substituted, or A ² represents an aromatic hydrocarbon group, A ² represents R ³ or OR ³ , R ³ represents an optionally substituted aliphatic or aromatic hydrocarbon group having 1 to 20 carbon atoms, and R ⁴ represents carbon Represents an aliphatic hydrocarbon group having a number of 1 or more and 20 or less, j and k each independently represent an integer of 1 to 1,000, l represents an integer of 1 to 100, and m represents 1 to 20 And n represents an integer of 1 or more and 1,000 or less.)

(V)
(In Formula (V), A ¹ represents NR ¹ R ² or OR ¹ , and R ¹ and R ² are each independently a hydrogen atom, an aliphatic group having 1 to 20 carbon atoms that may be substituted, or Represents an aromatic hydrocarbon group, A ² represents R ³ or OR ³ , R ³ represents an optionally substituted aliphatic or aromatic hydrocarbon group having 1 to 20 carbon atoms, and Y represents an oxygen atom Or NH, R ⁴ and R ⁵ each independently represent an aliphatic hydrocarbon group having 1 to 20 carbon atoms, j and k each independently represent an integer of 1 to 1,000, Represents an integer of 1 to 100, m represents an integer of 1 to 20, n represents an integer of 1 to 1,000, and p represents an integer of 0 to 1,000.)

(VI)
(In the formula (VI), A ¹ represents NR ¹ R ² or OR ¹ , and R ¹ and R ² are each independently a hydrogen atom, or an aliphatic group having 1 to 20 carbon atoms which may be substituted, or A ² represents an aromatic hydrocarbon group, A ² represents R ³ or OR ³ , R ³ represents an optionally substituted aliphatic or aromatic hydrocarbon group having 1 to 20 carbon atoms, and Z represents a divalent group. J and k each independently represent an integer of 1 to 1,000, l represents an integer of 1 to 100, m represents an integer of 1 to 20, and n represents 1 Represents an integer of 1,000 or more.)

In formulas (III) to (VI), R ¹ and R ² each independently represent a hydrogen atom or an optionally substituted aliphatic or aromatic hydrocarbon group having 1 to 20 carbon atoms, and is soluble From the viewpoint of productivity, etc., a hydrogen atom or an optionally substituted aliphatic hydrocarbon group having 3 to 20 carbon atoms is preferable. R ³ represents an optionally substituted aliphatic or aromatic hydrocarbon group having 1 to 20 carbon atoms, and has 4 to 18 carbon atoms that may be substituted from the viewpoint of solubility, productivity, and the like. Aliphatic or aromatic hydrocarbon groups are preferred. R ⁴ and R ⁵ each independently represent an aliphatic hydrocarbon group having 1 to 20 carbon atoms, and an aliphatic hydrocarbon group having 1 to 10 carbon atoms is preferable from the viewpoint of productivity.

  Examples of the aliphatic hydrocarbon group having 1 to 20 carbon atoms include methyl group, ethyl group, linear or branched propyl group, butyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group, tridecyl group, A hexadecyl group, an octadecyl group, etc. are mentioned, From the point of solubility, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a decyl group, a dodecyl group, a tridecyl group, a hexadecyl group, an octadecyl group, etc. are preferable.

  Examples of the aromatic hydrocarbon group having 1 to 20 carbon atoms include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a biphenylyl group. From the viewpoint of productivity and stability, a phenyl group and a naphthyl group are preferable. preferable.

  Examples of the substituent that may be substituted with an aliphatic or aromatic hydrocarbon group having 1 to 20 carbon atoms include a halogen atom, a hydroxy group, an amino group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group, and an alkylamino group. Group, a dialkylamino group, and the like. From the viewpoints of solubility and charge control characteristics, an alkyl group having 1 to 10 carbon atoms and a dialkylamino group are preferable.

As the divalent organic group in the formula (VI), —CH (CH ₃ ) — (CH ₂ ) ₂ C (═O) NH—, —C (CH ₃ ) (CN) — (CH ₂ ) ₂ C ( _{= O) NH -, - C} (CH 3) (CN) - (CH 2) 3 C (= O) NH- , and the like, from the viewpoint of _{manufacturability, -C (CH 3) (CN} ) - (CH ₂ ) ₂ C (═O) NH— is preferred.

  In formula (III), j and k each independently represent an integer of 1 or more and 1,000 or less, and an integer of 5 or more and 100 or less is preferable from the viewpoints of solubility and charge control characteristics.

  In the formulas (III) to (VI), l represents an integer of 1 to 100 and is preferably an integer of 1 to 10 in terms of solubility, charge control characteristics, and the like.

  In the formulas (IV) to (VI), m represents an integer of 1 to 20, and an integer of 3 to 10 is preferable from the viewpoint of manufacturability and the like. n represents an integer of 1 or more and 1,000 or less.

  In the formula (V), p represents an integer of 0 or more and 1,000 or less, and an integer of 10 or more and 300 or less is preferable from the viewpoint of solubility and manufacturability.

  The amount of the olefin / maleic acid derivative copolymer having a polysiloxane structure in the main chain or side chain in the liquid developer is, for example, from 0.01 parts by weight to 1 part by weight with respect to 100 parts by weight of the liquid developer. The range is preferable, and the range of 0.1 parts by mass to 0.5 parts by mass is more preferable. When the amount of the olefin / maleic acid derivative copolymer having a polysiloxane structure in the main chain or side chain with respect to the liquid developer is less than 0.01 parts by mass with respect to 100 parts by mass of the liquid developer, the charging property is inferior If the amount exceeds 1 part by mass, the conductivity may be too high, and the chargeability may be lowered.

  The weight average molecular weight of the olefin / maleic acid derivative copolymer having a polysiloxane structure in the main chain or side chain is preferably in the range of 1,000 or more and 100,000 or less, and is 5,000 or more and 20,000 or less. A range is more preferable. If the weight average molecular weight of the olefin / maleic acid derivative copolymer having a polysiloxane structure in the main chain or the side chain is less than 1,000, the compatibility with the liquid developer may not be sufficient. If it exceeds, the fixability of the developer may be inhibited.

[Method for producing liquid developer]
In the liquid developer according to the exemplary embodiment, the toner particles and the carrier liquid are mixed and pulverized using a dispersing machine such as a ball mill, a sand mill, an attritor, or a bead mill, and the toner particles are mixed in the carrier liquid. Obtained by dispersing. The dispersion of the toner particles in the carrier liquid is not limited to a disperser, and may be dispersed by rotating a special stirring blade at a high speed like a mixer, or by the shearing force of a rotor / stator known as a homogenizer. Alternatively, it may be dispersed by ultrasonic waves.

  The concentration of the toner particles in the carrier liquid should be in the range of 0.5% by mass or more and 40% by mass or less from the viewpoint of controlling the viscosity of the developer appropriately and facilitating the circulation of the developer in the developing machine. Is preferable, and the range of 1% by mass to 30% by mass is more preferable.

  Thereafter, the obtained dispersion liquid may be filtered using, for example, a filter such as a membrane filter having a pore diameter of about 100 μm to remove dust, coarse particles, and the like.

<Developer cartridge, process cartridge, image forming apparatus>
The image forming apparatus according to the present embodiment includes, for example, an image carrier (hereinafter sometimes referred to as “photosensitive member”), a charging unit that charges the surface of the image carrier, and a latent image ( The latent image forming means for forming the electrostatic latent image) and the latent image formed on the surface of the image holding member are developed with the liquid developer according to the embodiment held on the surface of the developer holding member. Developing means for forming a toner image, transfer means for transferring the toner image formed on the surface of the image carrier onto the recording medium, and fixing the toner image transferred to the recording medium onto the recording medium Fixing means to be formed.

  The image forming method according to the present embodiment includes, for example, a latent image forming step of forming a latent image on the surface of the image carrier, and a latent image formed on the surface of the image carrier. A developing process for forming the toner image by developing with the liquid developer according to the present embodiment held on the image, a transfer process for transferring the toner image formed on the surface of the image holding member onto the recording medium, and recording. And a fixing step of fixing the toner image transferred onto the medium to a recording medium to form a fixed image.

  In the image forming apparatus, for example, the part including the developing unit may have a cartridge structure (process cartridge) that is detachable from the main body of the image forming apparatus. The process cartridge is not particularly limited as long as it contains the liquid developer according to the present embodiment. The process cartridge includes, for example, a developing unit that stores the liquid developer according to the present embodiment and develops a latent image formed on the image carrier with the liquid developer to form a toner image. It is to be attached to and detached from.

  The developer cartridge according to the present embodiment is not particularly limited as long as it contains the liquid developer according to the present embodiment. The developer cartridge contains, for example, the liquid developer according to the present embodiment, and includes an image forming apparatus including a developing unit that forms a toner image by developing the latent image formed on the image holding member with the liquid developer. It is to be attached to and detached from.

  Hereinafter, an image forming apparatus using a liquid developer in the present embodiment will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present embodiment. The image forming apparatus 100 includes a photosensitive member (image holding member) 10, a charging device (charging unit) 20, an exposure device (latent image forming unit) 12, a developing device (developing unit) 14, and an intermediate transfer member (transfer). Means) 16, a cleaner (cleaning means) 18, and a transfer fixing roller (transfer means, fixing means) 28. The photosensitive member 10 has a cylindrical shape, and a charging device 20, an exposure device 12, a developing device 14, an intermediate transfer member 16, and a cleaner 18 are sequentially provided on the outer periphery of the photosensitive member 10.

  Hereinafter, the operation of the image forming apparatus 100 will be described.

  The charging device 20 charges the surface of the photoconductor 10 to a predetermined potential (charging process), and based on the image signal, the exposure device 12 exposes the charged surface with, for example, a laser beam to form a latent image (static image). Electrostatic latent image) is formed (latent image forming step).

  The developing device 14 includes a developing roller 14a and a developer storage container 14b. The developing roller 14a is provided such that a part thereof is immersed in the liquid developer 24 stored in the developer storage container 14b. The liquid developer 24 includes an insulating carrier liquid, toner particles containing a binder resin, and the charge control agent.

  In the liquid developer 24, the toner particles are dispersed. For example, the liquid developer 24 is further stirred by a stirring member provided in the developer container 14b. Variation in the position of the concentration of is reduced. Thus, the liquid developer 24 with reduced toner particle density variation is supplied to the developing roller 14a rotating in the direction of arrow A in the figure.

  The liquid developer 24 supplied to the developing roller 14a is conveyed to the photoconductor 10 in a state where the liquid supply 24 is limited to a constant supply amount by the regulating member, and at a position where the developing roller 14a and the photoconductor 10 are close (or in contact). It is supplied to the electrostatic latent image. As a result, the electrostatic latent image is visualized to become a toner image 26 (development process).

  The developed toner image 26 is conveyed to the photosensitive member 10 that rotates in the direction of arrow B in the figure, and is transferred to a paper (recording medium) 30. In this embodiment, the photosensitive member 26 is transferred before being transferred to the paper 30. The toner image is temporarily transferred to the intermediate transfer body 16 in order to improve the transfer efficiency to the recording medium including the separation efficiency of the toner image from the toner 10, and to perform fixing simultaneously with the transfer to the recording medium (intermediate transfer step). . At this time, a peripheral speed difference may be provided between the photosensitive member 10 and the intermediate transfer member 16.

  Next, the toner image conveyed in the direction of arrow C by the intermediate transfer body 16 is transferred to the paper 30 and fixed at the position of contact with the transfer and fixing roller 28 (transfer process, fixing process). The transfer fixing roller 28 sandwiches the paper 30 together with the intermediate transfer body 16, and causes the toner image on the intermediate transfer body 16 to adhere to the paper 30. As a result, the toner image is transferred to the paper 30, and the toner image is fixed on the paper to form a fixed image 29. The fixing of the toner image is preferably performed by applying a heating element to the transfer fixing roller 28 and applying pressure and heating. The fixing temperature is usually in the range of 120 ° C. or higher and 200 ° C. or lower.

  If the intermediate transfer member 16 has a roller shape as shown in FIG. 1, it forms a roller pair with the transfer fixing roller 28. Therefore, the intermediate transfer member 16 and the transfer fixing roller 28 conform to the fixing roller and the pressing roller in the fixing device, respectively. It shows a fixing function. That is, when the sheet 30 passes through the nip formed between the intermediate transfer body 16 and the transfer fixing roller 28, the toner image is transferred and heated and pressed against the intermediate transfer body 16 by the transfer fixing roller 28. The As a result, the binder resin in the toner particles constituting the toner image is softened, and the toner image is infiltrated into the fibers of the paper 30 to form a fixed image 29 on the paper 30.

  In this embodiment, fixing is performed simultaneously with the transfer to the paper 30. However, the transfer process and the fixing process may be performed separately, and the fixing may be performed after the transfer. In this case, the transfer roller for transferring the toner image from the photoconductor 10 has a function according to the intermediate transfer body 16.

  On the other hand, in the photoreceptor 10 that has transferred the toner image 26 to the intermediate transfer member 16, the toner particles remaining without being transferred are conveyed to a contact position with the cleaner 18 and collected by the cleaner 18. If the transfer efficiency is close to 100% and residual toner is not a problem, the cleaner 18 may not be provided.

  The image forming apparatus 100 may further include a neutralization device (not shown) that neutralizes the surface of the photoconductor 10 after the transfer and before the next charging.

  For example, the charging device 20, the exposure device 12, the developing device 14, the intermediate transfer member 16, the transfer fixing roller 28, and the cleaner 18 that are provided in the image forming apparatus 100 are all synchronized with the rotational speed of the photosensitive member 10. May be operated.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

[Example 1]
(Preparation of liquid developer)
Styrene acrylic resin (manufactured by Fujikura Kasei Co., Ltd., styrene-acrylic acid resin (molar ratio 60:40), weight average molecular weight: 380,000) to 60 parts by mass of cyan pigment (CI Pigment Blue 15: 3, Clariant) 40 parts by mass were added and kneaded with a pressure kneader. The kneaded product was coarsely pulverized to prepare a cyan pigment master batch.

Next, a mixture having the following composition was dissolved and dispersed in a ball mill for 24 hours.
Styrene acrylic resin (manufactured by Fujikura Kasei Co., Ltd., styrene-n-butyl acrylate resin (molar ratio 60:40), weight average molecular weight: 320,000, acid value 10 mgKOH / g): 75 parts by mass The above cyan pigment master batch : 25 parts by mass Ethyl acetate: 100 parts by mass

On the other hand, 50 parts by mass of calcium carbonate (manufactured by Maruo Calcium Co., Ltd., Luminous) as an aqueous dispersion prepared by dissolving 60 parts by mass of sodium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) in 400 parts by mass of ion-exchanged water. And dispersed with a ball mill for 24 hours to obtain a dispersion medium. 100 parts by mass of the mixture is added to 170 parts by mass of this dispersion medium, and the mixture is emulsified for 1 minute at 8,000 rpm to 24,000 rpm using an emulsifier (IKA, Ultratax T-50). Got. The above suspension was placed in a separable flask equipped with a stirrer, thermometer, cooling tube and nitrogen introduction tube, and the mixture was stirred at 60 ° C. for 3 hours while introducing nitrogen from the nitrogen introduction tube to distill off ethyl acetate. .
After standing to cool, 10% hydrochloric acid aqueous solution was added to the mixture to decompose calcium carbonate, solids were separated by a centrifuge, washed with 1 L of ion-exchanged water three times, and a volume average particle size of 3.5 μm. A slurry of toner particles was obtained.

  100 parts by weight of the cyan toner particle slurry obtained above was dispersed in 300 parts by weight of distilled water, and adjusted to pH 2 by adding 4 parts by weight of 1N hydrochloric acid. The mixture was filtered and washed with distilled water, then redispersed in 300 parts by mass of distilled water, and with stirring, 20 parts by mass of a 5% by mass aqueous solution of polyethyleneimine (weight average molecular weight 70,000; manufactured by Alfa Aeser) was added. The solution was gradually added dropwise, and stirring was continued for 1 hour after completion of the addition. After completion of the stirring, the dispersion was subjected to suction filtration and repeatedly washed with water, and then the obtained cake was freeze-dried at 20 ° C. for 24 hours to recover 57 parts by mass of dried cyan toner particles.

  20 parts by mass of the cyan toner particles obtained above were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) to obtain a liquid developer having a solid content concentration of 20% by mass. .

<Evaluation of charging characteristics>
(Charge polarity)
Two glass substrates with ITO processed to 5cm x 1cm (EHC: 100Ω / □) are sandwiched by a Naflon sheet (Azwan: 1cm x 1cm x 1.0mm) as an insulating spacer, and the electrode faces inward It was fixed to become. Place 1 mL of liquid developer sample in a disposable cell (Azwan: 12 × 12 × 45 mm), immerse the electrode substrate above, apply a DC voltage of 250 V for 30 seconds, and keep the voltage applied. And the adhesion state of the particles on the ITO electrode surfaces of the positive electrode and the negative electrode was observed to determine the charging characteristics. The results are shown in Table 1. In the following, the case where the charging property is ± indicates that the same amount of positive polarity particles and negative polarity particles are mixed, and the developer having such characteristics is used for a bright image area in an actual system. As a result, fogging occurs, so that it is not suitable for any system of positive charging system or negative charging system.
+: Adheres only to the negative electrode-: adheres only to the positive electrode ±: adheres to both electrodes-: does not adhere to both electrodes

(Charging strength)
For the liquid developers obtained in each Example and each Comparative Example, the potential difference was measured using a “microscopic laser zeta electrometer” ZC-3000 manufactured by Microtick Nithion, and evaluated according to the following five-stage criteria. did. The measurement is performed by diluting the liquid developer with a diluting solvent, putting it in a 10 mm transparent cell, applying a voltage of 300 V at 9 mm between the electrodes, and simultaneously observing the moving speed of the particles in the cell with a microscope. The calculation was performed by calculating the zeta potential from the value. The results are shown in Table 1.
A: Potential difference is +100 mV or more (very good)
B: Potential difference is +85 mV or more and less than +100 mV (good)
C: Potential difference is +70 mV or more and less than +85 mV (normal)
D: Potential difference is +50 mV or more and less than +70 mV (somewhat bad)
E: Potential difference is less than +50 mV (very bad)

  The toner particles can be collected from the liquid developer by the following method. The liquid developer is sedimented by centrifugation (1,000 rpm × 5 minutes), the supernatant is removed by decantation, and the toner particles are removed. The removed toner particles are washed with hexane, isopar or the like (the mixed solvent may be appropriately changed depending on the toner resin).

[Example 2]
100 parts by weight of the cyan toner particle slurry obtained in Example 1 was dispersed in 300 parts by weight of distilled water, and adjusted to pH 2 by adding 4 parts by weight of 1N hydrochloric acid. The mixture was separated by filtration and washed with distilled water, then redispersed in 300 parts by weight of distilled water, and while stirring, polyallylamine PAA-15C (15% by mass solution; manufactured by Nitto Bo Medical Co., Ltd., the above formula (I) In Example 1, a is about 300, and b is 0. 10 parts by mass of a weight average molecular weight: 15,000) was gradually added dropwise, and stirring was continued for 1 hour after the addition was completed. After completion of the stirring, the dispersion was subjected to suction filtration and repeatedly washed with water, and then the obtained cake was freeze-dried at 20 ° C. for 24 hours to recover 53 parts by mass of dried cyan toner particles.

  20 parts by mass of the cyan toner particles obtained above were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) to obtain a liquid developer having a solid content concentration of 20% by mass. . Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

[Example 3]
100 parts by weight of the cyan toner particle slurry obtained in Example 1 was dispersed in 300 parts by weight of distilled water, and adjusted to pH 2 by adding 4 parts by weight of 1N hydrochloric acid. This mixture was filtered and washed with distilled water, and then redispersed in 300 parts by mass of distilled water, and while stirring, polyallylamine PAA-1112 (15% by mass solution; manufactured by Nitto Bo Medical Co., Ltd., the above formula (I) In the above, a is 5 or more and 10 or less, b is 5 or more and 10 or less, and R ¹ and R ² are methyl groups. Stirring was continued for hours. After completion of the stirring, the dispersion was subjected to suction filtration and repeatedly washed with water, and then the obtained cake was freeze-dried at 20 ° C. for 24 hours to recover 58 parts by mass of dried cyan toner particles.

  20 parts by mass of the cyan toner particles obtained above were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) to obtain a liquid developer having a solid content concentration of 20% by mass. . Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

[Example 4]
20 parts by mass of the dried cyan toner particles obtained in Example 1 were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) and carboxy-modified silicone oil (X-22-3701E; Shin-Etsu). In Chemical Formula Co., Ltd., in the above formula (II), X and Y are hydrogen atoms, Z is COOH, R ³ and R ⁴ are methylene groups, and R ⁵ is an alkylene group (details unknown). (Molecular weight: 40,000) (Compound (II-1)) was mixed with 0.1 part by mass to obtain a liquid developer having a solid concentration of 20% by mass. Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

(II-1)

[Example 5]
20 parts by mass of the dried cyan toner particles obtained in Example 1 were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) and carboxy-modified silicone oil (X-22-3710; Shin-Etsu). In Chemical Formula Co., Ltd., in the above formula (II), X is COOH, Y and Z are hydrogen atoms, R ³ is an alkylene group (details are unknown), and R ⁴ and R ⁵ are methylene groups. Molecular weight: 1,450) (Compound (II-2)) was mixed with 0.1 part by mass to obtain a liquid developer having a solid concentration of 20% by mass. Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

(II-2)

[Example 6]
20 parts by mass of the dried cyan toner particles obtained in Example 1 were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) and carboxy-modified silicone oil (X-22-162C, Shin-Etsu). In Chemical Formula Co., Ltd., in the above formula (II), X and Y are COOH, Z is a hydrogen atom, R ³ and R ⁴ are alkylene groups (details unknown), and R ⁵ is a methylene group. Molecular weight: 4,600) (Compound (II-3)) 0.1 parts by mass was mixed to obtain a liquid developer having a solid content concentration of 20% by mass. Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

(II-3)

[Example 7]
20 parts by mass of the dried cyan toner particles obtained in Example 1 were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.2 parts by mass of the following compound (III-1). To obtain a liquid developer having a solid concentration of 20% by mass. Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

(III-1)

Compound (III-1) was synthesized as follows.
(Precursor synthesis)
1-octadecene 25.5 parts by mass, maleic anhydride 10 parts by mass, and (3-methacryloxy) propylpolydimethylsiloxane (Silaplane FM-0725; manufactured by JNC) 20 parts by mass were dissolved in 50 parts by mass of toluene. After carrying out nitrogen substitution, the temperature was raised to 70 ° C. with an oil bath, a solution having 0.5 parts by mass of benzoyl peroxide dissolved in 5 parts by mass of toluene was added, and the mixture was stirred at 80 ° C. for 20 hours. After completion of the reaction, the mixture was poured into 800 parts by mass of 2-propanol, and the resulting precipitate was filtered with suction, washed with 2-propanol, and then dried under reduced pressure to obtain 35.5 parts by mass of the following precursor (light yellow solid). Obtained.

  5.5 parts by mass of the above precursor, 2.6 parts by mass of hexadecylamine, and 0.1 parts by mass of pyridine were dissolved in 25 parts by mass of xylene and stirred at 130 ° C. for 20 hours under a nitrogen stream. After completion of the reaction, the mixture was poured into 500 parts by mass of methanol, and the resulting precipitate was filtered with suction, washed with methanol, and dried under reduced pressure to obtain 6.3 parts by mass of a pale yellow solid. It was Mw: 36,000 (polystyrene conversion) when the weight average molecular weight of the obtained compound (III-1) was measured by GPC.

[Example 8]
20 parts by mass of the dried cyan toner particles obtained in Example 1 were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.1 part by mass of the following compound (III-2). To obtain a liquid developer having a solid concentration of 20% by mass. Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

(III-2)

  Compound (III-2) was synthesized as follows. The precursor used in Example 7 5.5 parts by mass, N, N-dimethyl-2,2-dimethyl-1,3-propanediamine 1.4 parts by mass, and pyridine 0.1 parts by mass xylene 25 parts by mass The solution was dissolved in a part and stirred at 130 ° C. for 20 hours under a nitrogen stream. After completion of the reaction, the mixture was poured into 300 parts by mass of methanol, and the resulting precipitate was filtered with suction, washed with methanol, and dried under reduced pressure to obtain compound (III-2) as a pale pink solid. It was Mw: 33,000 (polystyrene conversion) when the weight average molecular weight of the obtained compound (III-2) was measured by GPC.

[Example 9]
20 parts by mass of the dried cyan toner particles obtained in Example 2 were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.1 part by mass of the compound (III-2). To obtain a liquid developer having a solid concentration of 20% by mass. Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

[Example 10]
20 parts by mass of the dried cyan toner particles obtained in Example 3 were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) and carboxy-modified silicone oil (X-22-3701E; Shin-Etsu). A liquid developer having a solid content concentration of 20% by mass was obtained by mixing with 0.1 part by mass of Compound (II-1) manufactured by Chemical Industry Co., Ltd. Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

[Example 11]
20 parts by mass of the dried cyan toner particles obtained in Example 3 were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) and carboxy-modified silicone oil (X-22-3710; Shin-Etsu). A liquid developer having a solid concentration of 20% by mass was obtained by mixing with 0.1 part by mass of Compound (II-2), manufactured by Chemical Industry Co., Ltd. Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

[Example 12]
20 parts by mass of the dried cyan toner particles obtained in Example 3 were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.1 part by mass of the compound (III-1). To obtain a liquid developer having a solid concentration of 20% by mass. Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

[Example 13]
20 parts by mass of the dried cyan toner particles obtained in Example 3 were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.1 part by mass of the compound (III-2). To obtain a liquid developer having a solid concentration of 20% by mass. Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

[Example 14]
As a styrene acrylic resin, instead of a styrene-n-butyl acrylate resin (Fujikura Kasei Co., Ltd., weight average molecular weight: 320,000, acid value 10 mgKOH / g), a styrene acrylic resin having no acidic group (Fujikura) Except for using a styrene-n-butyl acrylate resin (molar ratio 60:40), a weight average molecular weight: 320,000, and an acid value of 0 mgKOH / g) manufactured by Kasei Co., Ltd. 57 parts by mass of dry cyan toner particles were obtained to obtain a liquid developer having a solid content concentration of 20% by mass.

[Example 15]
As the styrene acrylic resin, instead of styrene-n-butyl acrylate resin (Fujikura Kasei Co., Ltd., weight average molecular weight: 320,000, acid value 10 mgKOH / g), styrene acrylic resin (Fujikura Kasei Co., Ltd., 57 masses of dry cyan toner particles in the same manner as in Example 1 except that styrene-n-butyl acrylate resin (molar ratio 60:40), weight average molecular weight: 320,000, acid value 20 mgKOH / g) was used. Parts were obtained to obtain a liquid developer having a solid content concentration of 20% by mass.

[Example 16]
As the styrene acrylic resin, instead of styrene-n-butyl acrylate resin (Fujikura Kasei Co., Ltd., weight average molecular weight: 320,000, acid value 10 mgKOH / g), styrene acrylic resin (Fujikura Kasei Co., Ltd., 57 masses of dry cyan toner particles in the same manner as in Example 1 except that styrene-n-butyl acrylate resin (molar ratio 60:40), weight average molecular weight: 320,000, acid value 5 mgKOH / g) was used. Parts were obtained to obtain a liquid developer having a solid content concentration of 20% by mass.

[Example 17]
As the styrene acrylic resin, instead of styrene-n-butyl acrylate resin (Fujikura Kasei Co., Ltd., weight average molecular weight: 320,000, acid value 10 mgKOH / g), styrene acrylic resin (Fujikura Kasei Co., Ltd., 57 masses of dry cyan toner particles in the same manner as in Example 1 except that styrene-n-butyl acrylate resin (molar ratio 60:40), weight average molecular weight: 320,000, acid value 60 mgKOH / g) was used. Parts were obtained to obtain a liquid developer having a solid content concentration of 20% by mass.

[Example 18]
As the styrene acrylic resin, instead of styrene-n-butyl acrylate resin (Fujikura Kasei Co., Ltd., weight average molecular weight: 320,000, acid value 10 mgKOH / g), styrene acrylic resin (Fujikura Kasei Co., Ltd., Dry cyan toner particles in the same manner as in Example 1 except that styrene-n-butyl acrylate resin (molar ratio 60:40), weight average molecular weight: 320,000, acid value 0.5 mgKOH / g) was used. 57 parts by mass was obtained to obtain a liquid developer having a solid content concentration of 20% by mass.

[Comparative Example 1]
The slurry of cyan toner particles used in Example 1 was lyophilized as it was at 20 ° C. for 24 hours to recover 60 parts by mass of the dried cyan toner particles.

  20 parts by mass of the obtained dry cyan toner particles were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) to obtain a liquid developer having a solid content concentration of 20% by mass. Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 2]
20 parts by mass of the dried cyan toner particles obtained in Comparative Example 1 were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) and carboxy-modified silicone oil (X-22-3701E; Shin-Etsu). A liquid developer having a solid content concentration of 20% by mass was obtained by mixing with 0.1 part by mass of Compound (II-1) manufactured by Chemical Industry Co., Ltd. Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 3]
20 parts by mass of the dried cyan toner particles obtained in Comparative Example 1 were mixed with 80 parts by mass of silicone oil (KE-96L-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.1 part by mass of the compound (III-2). To obtain a liquid developer having a solid concentration of 20% by mass. Thereafter, the charging characteristics were determined in the same manner as in Example 1. The results are shown in Table 1.

  As described above, in the example using the liquid developer containing the toner particles containing the styrene acrylic resin, which was surface-treated with the polymer amines, the positive chargeability was excellent as compared with the comparative example.

  DESCRIPTION OF SYMBOLS 10 Photosensitive body (image holding body), 12 Exposure apparatus (latent image forming means), 14 Developing apparatus (developing means), 14a Developing roller (developer holding body), 14b Developer accommodating container, 16 Intermediate transfer body (transfer means) ), 18 cleaner (cleaning means), 20 charging device (charging means), 24 liquid developer, 26 toner image, 28 transfer fixing roller (transfer means, fixing means), 29 fixed image, 30 paper (recording medium), 100 Image forming apparatus.

Claims (9)

Carrier liquid,
Toner particles containing styrene acrylic resin, surface treated with polymeric amines;
A liquid developer comprising:   The liquid developer according to claim 1, wherein the styrene acrylic resin has an acidic group in a molecule.   The liquid developer according to claim 1, wherein the high molecular amine is a polyalkyleneimine. The liquid developer according to claim 1, wherein the high-molecular amine is a polyallylamine represented by the following general formula (I).

(I)
(In formula (I), R ¹ and R ² each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 20 carbon atoms, and a and b each independently represent 100 to 1,000. The following integers are shown.) The liquid developer according to any one of claims 1 to 4, wherein the carrier liquid contains a carboxyl group-containing silicone compound represented by the following general formula (II).

(II)
(In the formula (II), X, Y and Z each independently represent a hydrogen atom or a carboxyl group, and at least one of X, Y and Z represents a carboxyl group. N is an integer of 1 to 10. R ³ , R ⁴ and R ⁵ are each independently a single bond or a divalent aliphatic carbon atom having 1 to 20 carbon atoms. Indicates a hydrogen group.) The olefin / maleic acid derivative copolymer having a polysiloxane structure in the main chain or side chain, represented by the following formula (III), is contained in the carrier liquid. 2. The liquid developer according to item 1.

(III)
(In Formula (III), A ¹ represents NR ¹ R ² or OR ¹ , and R ¹ and R ² are each independently a hydrogen atom, or an aliphatic group having 1 to 20 carbon atoms that may be substituted, or Represents an aromatic hydrocarbon group, A ² represents R ³ or OR ³ , R ³ represents an optionally substituted aliphatic or aromatic hydrocarbon group having 1 to 20 carbon atoms, and X represents a main chain Or a divalent organic group having a polysiloxane structure in the side chain, j and k each independently represent an integer of 1 to 1,000, and l represents an integer of 1 to 100.)   A developer cartridge containing the liquid developer according to claim 1.   A process cartridge containing the liquid developer according to claim 1. An image carrier,
Latent image forming means for forming a latent image on the surface of the image carrier;
The latent image formed on the surface of the image carrier is developed by the liquid developer according to claim 1 held on the surface of the developer carrier to form a toner image. Developing means,
Transfer means for transferring the toner image formed on the surface of the image carrier onto a recording medium;
Fixing means for fixing the toner image transferred to the recording medium to the recording medium to form a fixed image;
An image forming apparatus comprising: